Added configuration pass that adds Twig Loaders

- Added compiler class which picks up any services tagged "twig.loader"
- If there is one loader registered we set the alias to this loader
- If there is more than one we set the alias to a chain loader and all
  the loaders to it
- If there is no loaders we throw an Exception

src/Symfony/Bundle/TwigBundle/CHANGELOG.md

@@ -4,6 +4,7 @@ CHANGELOG
 2.2.0
 -----
 
+ * added support for multiple loaders via the "twig.loader" tag.
  * added automatic registration of namespaced paths for registered bundles
  * added support for namespaced paths
 

src/Symfony/Bundle/TwigBundle/DependencyInjection/Compiler/TwigLoaderPass.php

@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Bundle\TwigBundle\DependencyInjection\Compiler;
+
+use Symfony\Component\DependencyInjection\Reference;
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
+use Symfony\Component\DependencyInjection\Exception\LogicException;
+
+/**
+ * If there are any tagged loaders replace
+ * default filesystem loader with chain loader
+ *
+ * Add tagged loaders to chain loader
+ *
+ * @author Daniel Leech <daniel@dantleech.com>
+ */
+class TwigLoaderPass implements CompilerPassInterface
+{
+    public function process(ContainerBuilder $container)
+    {
+        if (false === $container->hasDefinition('twig')) {
+            return;
+        }
+
+        // register additional template loaders
+        $loaderIds = $container->findTaggedServiceIds('twig.loader');
+
+        if (count($loaderIds) === 0) {
+            throw new LogicException('No twig loaders found. You need to tag at least one loader with "twig.loader"');
+        }
+
+        if (count($loaderIds) === 1) {
+            $container->setAlias('twig.loader', key($loaderIds));
+        } else {
+            $chainLoader = $container->getDefinition('twig.loader.chain');
+            foreach (array_keys($loaderIds) as $id) {
+                $chainLoader->addMethodCall('addLoader', array(new Reference($id)));
+            };
+            $container->setAlias('twig.loader', 'twig.loader.chain');
+        }
+    }
+}
+

src/Symfony/Bundle/TwigBundle/Resources/config/twig.xml

@@ -7,6 +7,7 @@
     <parameters>
         <parameter key="twig.class">Twig_Environment</parameter>
         <parameter key="twig.loader.filesystem.class">Symfony\Bundle\TwigBundle\Loader\FilesystemLoader</parameter>
+        <parameter key="twig.loader.chain.class">Twig_Loader_Chain</parameter>
         <parameter key="templating.engine.twig.class">Symfony\Bundle\TwigBundle\TwigEngine</parameter>
         <parameter key="twig.cache_warmer.class">Symfony\Bundle\TwigBundle\CacheWarmer\TemplateCacheCacheWarmer</parameter>
         <parameter key="twig.extension.trans.class">Symfony\Bridge\Twig\Extension\TranslationExtension</parameter>
@@ -41,8 +42,11 @@
         <service id="twig.loader.filesystem" class="%twig.loader.filesystem.class%" public="false">
             <argument type="service" id="templating.locator" />
             <argument type="service" id="templating.name_parser" />
+            <tag name="twig.loader"/>
         </service>
 
+        <service id="twig.loader.chain" class="%twig.loader.chain.class%" public="false"/>
+
         <service id="twig.loader" alias="twig.loader.filesystem" />
 
         <service id="templating.engine.twig" class="%templating.engine.twig.class%" public="false">

src/Symfony/Bundle/TwigBundle/Tests/DependencyInjection/Compiler/TwigLoaderPassTest.php

@@ -0,0 +1,87 @@
+<?php
+
+namespace symfony\src\Symfony\Bundle\TwigBundle\Tests\DependencyInjection\Compiler;
+
+use Symfony\Component\DependencyInjection\ContainerBuilder;
+use Symfony\Component\DependencyInjection\Definition;
+use Symfony\Bundle\TwigBundle\DependencyInjection\Compiler\TwigLoaderPass;
+
+class TwigLoaderPassTest extends \PHPUnit_Framework_TestCase
+{
+    public function setUp()
+    {
+        $this->builder = $this->getMock('Symfony\Component\DependencyInjection\ContainerBuilder');
+        $this->chainLoader = new Definition('loader');
+        $this->pass = new TwigLoaderPass();
+    }
+
+    public function testMapperPassWithOneTaggedLoaders()
+    {
+        $serviceIds = array(
+            'test_loader_1' => array(
+            ),
+        );
+
+        $this->builder->expects($this->once())
+            ->method('hasDefinition')
+            ->with('twig')
+            ->will($this->returnValue(true));
+        $this->builder->expects($this->once())
+            ->method('findTaggedServiceIds')
+            ->with('twig.loader')
+            ->will($this->returnValue($serviceIds));
+        $this->builder->expects($this->once())
+            ->method('setAlias')
+            ->with('twig.loader', 'test_loader_1');
+
+        $this->pass->process($this->builder);
+    }
+
+    public function testMapperPassWithTwoTaggedLoaders()
+    {
+        $serviceIds = array(
+            'test_loader_1' => array(
+            ),
+            'test_loader_2' => array(
+            ),
+        );
+
+        $this->builder->expects($this->once())
+            ->method('hasDefinition')
+            ->with('twig')
+            ->will($this->returnValue(true));
+        $this->builder->expects($this->once())
+            ->method('findTaggedServiceIds')
+            ->with('twig.loader')
+            ->will($this->returnValue($serviceIds));
+        $this->builder->expects($this->once())
+            ->method('getDefinition')
+            ->with('twig.loader.chain')
+            ->will($this->returnValue($this->chainLoader));
+        $this->builder->expects($this->once())
+            ->method('setAlias')
+            ->with('twig.loader', 'twig.loader.chain');
+
+        $this->pass->process($this->builder);
+        $calls = $this->chainLoader->getMethodCalls();
+        $this->assertEquals(2, count($calls));
+        $this->assertEquals('addLoader', $calls[0][0]);
+    }
+
+    /**
+     * @expectedException Symfony\Component\DependencyInjection\Exception\LogicException
+     */
+    public function testMapperPassWithZeroTaggedLoaders()
+    {
+        $this->builder->expects($this->once())
+            ->method('hasDefinition')
+            ->with('twig')
+            ->will($this->returnValue(true));
+        $this->builder->expects($this->once())
+            ->method('findTaggedServiceIds')
+            ->with('twig.loader')
+            ->will($this->returnValue(array()));
+
+        $this->pass->process($this->builder);
+    }
+}

src/Symfony/Bundle/TwigBundle/TwigBundle.php

@@ -14,6 +14,7 @@ namespace Symfony\Bundle\TwigBundle;
 use Symfony\Component\HttpKernel\Bundle\Bundle;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Bundle\TwigBundle\DependencyInjection\Compiler\TwigEnvironmentPass;
+use Symfony\Bundle\TwigBundle\DependencyInjection\Compiler\TwigLoaderPass;
 use Symfony\Bundle\TwigBundle\DependencyInjection\Compiler\ExceptionListenerPass;
 
 /**
@@ -28,6 +29,7 @@ class TwigBundle extends Bundle
         parent::build($container);
 
         $container->addCompilerPass(new TwigEnvironmentPass());
+        $container->addCompilerPass(new TwigLoaderPass());
         $container->addCompilerPass(new ExceptionListenerPass());
     }
 }